This contract provides for a multiple-arm randomized clinical trial of 1,200 women using four formulations of marketed nonoxynol-9 spermicides for the prevention of pregnancy. The study will determine the probability of pregnancy among women exposed to an intensive educational and motivational intervention designed to promote consistent and correct use of the spermicide. Secondary endpoint:s of interest include the incidence of adverse side-effects, and the acceptability of the four formulations.